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Abstract:

A method and device is provided for accessing a target location within a
branched network. The device may be passed through the working channel of
a standard endoscope and includes a three-dimensional location sensor at
its distal tip and an expandable extended working channel. The device has
a very thin body proximal of the distal sensor such that, once the sensor
is extended outside of the working channel of the endoscope, nearly all
of the working channel may be used to pass tools through the extended
working channel of the device.

Claims:

1. A device insertable through a working channel of an endoscope
comprising: a location mechanism capable of generating location
information pertaining to the location of the device; a flexible sheath
encompassing said location mechanism and defining a lumen, said lumen
capable of expanding to accommodate a device inserted through said lumen.

2. The tool of claim 1 wherein said location mechanism comprises a sensor
at a distal end of said device and wires leading from said sensor to a
proximal end of said device, said wires capable of carrying a signal from
said sensor.

3. The tool of claim 1 wherein said sheath comprises a material selected
from the group consisting of: polyamide, polyethylene, polyurethane,
polyester, pylon and silicone.

4. The tool of claim 2 wherein said wires comprise a curve.

5. The tool of claim 1 wherein said sheath comprises a curve.

6. The tool of claim 1 wherein said device comprises a curve.

7. The tool of claim 1 wherein said device further comprises a steering
wire.

8. The tool of claim 2 further comprising a steering device.

9. The tool of claim 8 wherein said steering device comprises said wires.

10. A method of accessing a target location within a patient comprising:
navigating an endoscope toward said target location; advancing a device
through a working channel of said endoscope, said device including a
location mechanism and a flexible sheath defining a lumen; anchoring a
distal end of said device proximate said target location; withdrawing
said endoscope from said patient over said device; passing a tool through
said flexible sheath to said target location.

12. The method of claim 10 wherein advancing a device through a working
channel of said endoscope comprises using said location mechanism to
assist in navigating said device to said target location.

13. The method of claim 10 wherein advancing a device through a working
channel of said endoscope, said device including a location mechanism and
a flexible sheath defining a lumen, comprises advancing a device through
a working channel of said endoscope, said device including a location
mechanism and a flexible sheath defining a lumen, said location mechanism
comprising a sensor at a distal end of said device and wires leading from
said sensor to a proximal end of said device, said wires capable of
carrying a signal from said sensor.

14. The method of claim 10 wherein advancing a device through a working
channel of said endoscope, said device including a location mechanism and
a flexible sheath defining a lumen, comprises advancing a device through
a working channel of said endoscope, said device including a location
mechanism and a flexible sheath defining a lumen, said sheath comprises a
material selected from the group consisting of: polyamide, polyethylene,
polyurethane, polyester, pylon and silicone.

15. A method of accessing a target location within a patient comprising:
introducing a device, said device including a location mechanism and a
flexible sheath defining a lumen, into a patient; using said location
mechanism to navigate said device to said target location; passing a tool
through said flexible sheath to said target location.

16. The method of claim 15 further comprising anchoring a distal end of
said device proximate said target location prior to said passing a tool
through said flexible sheath to said target location.

17. The method of claim 15 wherein introducing a device, said device
including a location mechanism and a flexible sheath defining a lumen,
into a patient, comprises introducing a device, said device including a
location mechanism and a flexible sheath defining a lumen, into a
patient, said location mechanism comprising comprising a sensor at a
distal end of said device and wires leading from said sensor to a
proximal end of said device, said wires capable of carrying a signal from
said sensor.

18. The method of claim 15 wherein introducing a device, said device
including a location mechanism and a flexible sheath defining a lumen,
into a patient, comprises introducing a device, said device including a
location mechanism and a flexible sheath defining a lumen, into a
patient, said said sheath comprises a material selected from the group
consisting of: polyamide, polyethylene, polyurethane, polyester, pylon
and silicone.

[0002] The present invention relates to catheters or elongated working
channels for use in medical procedures. More particularly, the present
invention relates to a locatable probe designed to be deployed through
the working channel of a bronchoscope and providing an expandable pathway
to a distal target.

BACKGROUND OF THE INVENTION

[0003] Catheters or elongated working channels are a staple device in
performing noninvasive medical procedure. The advantages of noninvasive
procedures are numerous and include decreased risk of infection,
decreased tissue damage, and shorter recovery periods. Unfortunately, the
types of procedures that can be preformed utilizing noninvasive
techniques is often limited by the size of the body lumen through which
the procedure will be conducted and, to an equal extent, the size of the
catheter or working channel inserted into the body lumen through which
the tools for conducting the procedures will be passed through.

[0004] Catheters or elongated working channels are often supplied in
standard sizes specific to a particular medical field or application. For
example, in procedures involving the lung or bronchial tree, a
bronchoscope is typically employed to span from the mouth, through the
trachea, to proximal locations in the primary branches of the bronchial
tree. Bronchoscopes generally have within their structure a working
channel through which devices may be passed to access and perform
procedures within the lungs. This working channel typically has an inner
diameter of 2.8 mm. Therefore, all noninvasive pulmonary procedures
utilizing a bronchoscope are limited to employing only those tools and
devices that can fit within a 2.8 mm working channel.

[0005] Due to the size limitation of the bronchoscope's working channel,
it is often necessary for a physician to pass a first tool or device
through the working channel, retract the first device, pass a second
device through the channel, and repeat this process several times with
either the same or different devices. This method not only lengthens the
procedure time but also introduces the possibility that the bronchoscope
or elongated working channel through which devices are passed may migrate
from their desired locations.

[0006] This limited working channel diameter not only dictates the size of
the tools and devices a physician can use but also the size of tissue
samples that may be obtained from a patient. Again, in the case of
bronchoscopes, in order to obtain a sample of tissue at a point of
interest, an extended working channel is typically passed through the
working channel of the bronchoscope and positioned proximate to the point
of interest. The extended working channel (or "EWC") is a catheter having
an outside diameter of less than 2.8 mm. A biopsy needle is then passed
through the EWC, used to extract the sample, and retracted from the
channel. Because the EWC has an outside diameter of less than 2.8 mm, it
follows that the inside diameter of the EWC is significantly smaller. Due
to the limited diameter of the EWC, the biopsy device will necessarily be
quite small. As a result the tissue sample obtained will also be very
small. The limited size of the tissue samples that can be obtained in
this manner, in turn, often necessitate repeating the tissue extraction
and sampling process several times in order to obtain a reasonable
representation of the tissue characteristics within the area of interest.

[0007] In the case of bronchoscopes, the 2.8 mm diameter limitation is not
dictated by the constraints and characteristics of the bronchial tree. To
the contrary, the tissue forming the airways of the bronchial tree are
quite elastic, distal of the cartilagenous zone. These lumens are safely,
and easily expanded and capable of receiving catheters and elongated
working channels of significantly greater diameters than currently used.
The risk of trauma does not arise from radially stretching the airways.
Rather, injury is more likely to be caused by longitudinally advancing a
relatively large, less flexible device through the airways, thereby
placing undue axial, rather than radial, pressure on the airways and
branches.

[0008] There is a need in the field for a catheter or EWC that can be
initially passed through the working channel of a conventional endoscope,
bronchoscope or similar device but that upon placement, may radially
expand once deployed within the body lumen. Thereby providing a elongated
working channel through which a physician may simultaneously pass
multiple tools or devices, larger tools or devices, and extract larger
tissue samples.

[0009] Ideally, this EWC would also be locatable by a three-dimensional
navigation system. The working channel of a bronchoscope ends at the
distal end of the bronchoscope, which is also where the lens of the scope
is located. The working channel allows a physician to access tissue with
a tool while watching the tool through the scope. Using an EWC however,
often extends the tool past the viewing range of the scope. This is
especially true in the lungs where the airways narrow quickly, preventing
the use of the scope in the distal airways.

[0010] Three dimensional tracking technology has allowed an EWC to be
safely and accurately navigated into the distal airways, well past the
reach of the bronchoscope. This tracking technology typically utilizes a
small location sensor, preferably providing tracking data in six degrees
of freedom, at a distal tip of a probe. Suitable sensors, sensing
techniques and related methods and devices are disclosed in U.S. Pat.
Nos. 6,188,355; 6,226,543; 6,558,333; 6,574,498; 6,593,884; 6,615,155;
6,702,780; 6,711,429; 6,833,814; 6,974,788; and 6,996,430, all to Gilboa
or Gilboa et al.; and U.S. Published Applications Pub. Nos. 2002/0193686;
2003/0074011; 2003/0216639; 2004/0249267 to either Gilboa or Gilboa et
al. All of these references are incorporated herein in their entireties.

OBJECTS AND SUMMARY OF THE INVENTION

[0011] A device and method for allowing the placement of a larger biopsy
tool at distal locations in a branched structure while still utilizing
the working channel of a standard bronchoscope. The device includes a
locatable probe that can be extended out of the working channel and
navigated distally therefrom. The probe includes a lumen formed of an
expandable material that essentially provides a radially expanding EWC.

[0012] In certain embodiments, the radially expandable working channel or
catheter may further employ an anchoring mechanism for securing a distal
end of the device within a patient lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other aspects, features and advantages of which
embodiments of the invention are capable of will be apparent and
elucidated from the following description of embodiments of the present
invention, reference being made to the following drawings.

[0014] FIG. 1 is perspective view of a preferred embodiment of a device
according to the present invention;

[0015] FIG. 2 is a perspective view of a distal end of a preferred
embodiment of a device according to the present invention; and

[0016] FIG. 3 is a perspective view of a preferred embodiment of A device
according to the present invention with a biopsy tool being passed
therethrough.

DESCRIPTION OF EMBODIMENTS

[0017] Specific embodiments of the invention will now be described with
reference to the accompanying drawings. This invention may, however, be
embodied in many different forms and should not be construed as limited
to the embodiments set forth herein; rather, these embodiments are
provided so that this disclosure will be thorough and complete, and will
fully convey the scope of the invention to those skilled in the art. The
terminology used in the detailed description of the embodiments
illustrated in the accompanying drawings is not intended to be limiting
of the invention. In the drawings, like numbers refer to like elements.

[0018] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this invention
belongs. It will be further understood that terms, such as those defined
in commonly used dictionaries, should be interpreted as having a meaning
that is consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense unless
expressly so defined herein.

[0019] Referring now to FIG. 1, there is shown an embodiment of a device
20 of the present invention, extending through a standard bronchoscope
10. The bronchoscope 10 is shown as having a working channel 12 and an
optical lens 14. It is understood, however, that the bronchoscope 10
shown is just an illustrative representation of a standard bronchoscope
having a working channel 12 and that the present invention 20 is designed
for use with any bronchoscope or endoscope.

[0020] The device 20 generally includes a sensor 20, sensor wires 24, and
a flexible sheath 30. The sheath 30 encompasses the sensor 22 and the
wires 24. Preferably, the sheath 30 encases the sensor 22 and the wires
24 within a wall of the sheath 30. The remaining material of the sheath
forms a thin, flexible wall around an expandable lumen 32, shown best in
FIG. 2, which is an enlarged view of a distal end 26 of the device 20.

[0021] FIG. 3 shows the device 20 being extended from the working channel
12 of a bronchoscope 10. As shown, once the sensor 22 exits the working
channel 12, the wires 24 and the sheath 30 are all that remain in the
working channel 12. Due to the small profile of the wires 24, and the
thin, flexible nature of the sheath 30, nearly all of the 2.8 mm working
channel lumen remains available for passing a tool, such as a biopsy
tool, therethrough.

[0022] In FIG. 3 a tool 40 is shown in phantom lines passing through the
lumen 32 of the device 20 of the present invention. The sheath 30
stretches to accommodate the tool 40 as the tool passes through the lumen
32. Preferably, in order to facilitate smooth passage of the tool 40, the
sheath 30 is constructed of a biologically friendly, expandable material
that is also strong as well as slippery. Non-limiting examples of
acceptable materials include: polyamide, polyethylene, polyurethane,
polyester, pylon, and silicone.

[0023] The body of the device 20, proximal of the sensor 22, is
contemplated as being limited to merely the wires 24, leading to and from
the sensor 22, and the sheath 30 material. Keeping the body limited to
these components reduces the profile. Additionally, however, it may be
desirable to provide the device with at least some steerability. As such,
the wires 24, sheath 30, or both may be either formed with a gentle
curve, provided with a steering wire.

[0024] In one embodiment, steerability is provided by using the wires 24
as steering wires. By gently pulling one wire relative to the other, the
sensor 22 turns slightly in the direction of the pulled wire. The
proximal ends of the wire may be fed through a prior art steering device
to effect this, as long as connection is made to a navigation system.

[0025] In operation, certain embodiments of the present invention may be
utilized in conjunction with conventional medical endoscopes. For
example, the above described embodiments may conform to an initial
non-expanded outer diameter less than that of the interior diameter of
the working channel of a endoscope such as, for example, a bronchoscope.
The radially expandable EWC may first be passed through the working
channel of the bronchoscope, optionally using said sensor to assist in
navigation of said expandable EWC. The distal end of the EWC may then be
anchored proximate to a point of interest within the patient. Once the
EWC is secured at the point of interest, the bronchoscope may be
withdrawn over the anchored EWC from the patient's airway. With the
constraint of the bronchoscope's limited diameter working channel
removed, the physician may proceed with expanding and/or passing the
desire devices and tools through the radially expandable EWC.

[0026] Alternatively, radially expandable EWCs according to the present
invention may also be employed without the aid or otherwise absent a
conventional endoscope. For example, a guidewire or steerable catheter
may simply be navigated to the point of interest within the patient. The
radially expandable EWC may then be passed over the guidewire or
steerable catheter. The physician may then anchor the EWC proximate to
the region of interest and proceed with expanding and/or passing the
desire devices and tools through the radially expandable EWC.

[0027] Although the invention has been described in terms of particular
embodiments and applications, one of ordinary skill in the art, in light
of this teaching, can generate additional embodiments and modifications
without departing from the spirit of or exceeding the scope of the
claimed invention. Accordingly, it is to be understood that the drawings
and descriptions herein are proffered by way of example to facilitate
comprehension of the invention and should not be construed to limit the
scope thereof.

Patent applications by Paige B. Hastings, Bloomington, MN US

Patent applications in class With tool carried on endoscope or auxillary channel therefore

Patent applications in all subclasses With tool carried on endoscope or auxillary channel therefore